Method for Repairing a Refractory Lining of a Metallurgical Vessel in the Hot State

ABSTRACT

A method relates in particular to the repair of a refractory lining of a metallurgical vessel ( 10 ) in the hot state. This repair takes place here by means of an supplying apparatus ( 15 ). In addition, recording of at least the worn regions and monitoring of the repair are carried out by means of a device ( 20 ). Before, during and/or after the supplying of at least a partial region of the areas ( 13 ) of the refractory lining ( 12 ) of the vessel ( 10 ) to be repaired or the gunning jet ( 18 ) is recorded photographically here with visualisation of the temperature ranges ( 26, 27, 28 ), and this results in an evaluation with regard to different parameters such as properties, layer thickness and/or distribution of the supplied material. It has been demonstrated that by means of this visualisation of the temperature ranges of the areas to be repaired and of the refractory material during supplying different parameters can be established very accurately, and as a result optimal coating of the wall lining can be achieved.

The invention relates to a method, in particular for repairing a refractory lining of a metallurgical vessel in the hot state according to the preamble to Claim 1 and to a corresponding device according to Claim 8.

According to publication EP-A-0 039 212 a remote-controlled injection apparatus for repairing a refractory lining of a metallurgical vessel at increased temperature is disclosed. This apparatus has a rotatable, vertical line that has a nozzle on its lower end. The supply of a fluidized flow of particulate refractory material is delivered, pressurized, to the line. Aligning means are used to align the line and the nozzle horizontally and vertically within the vessel close to a region of the lining to be repaired.

A television camera is attached to the line close to the nozzle in order to observe the inside of the vessel so as to locate the aforementioned region and to monitor the repair. This camera is disposed within a housing which is equipped with a transparent, heat-resistant opening in the line of sight of the lens. Moreover, a cooling device is attached to this housing in order to keep the camera cool, and temperature sensors are attached to a connection to the outside. With the aid of this camera the areas to be repaired can be visualized by a user, and so it is made possible for him to operate the gunning lance from outside of the hot vessel.

Another system for repairing and monitoring a refractory lining is described in publication U.S. Pat. No. 6,780,351 wherein a laser is guided into a hot furnace or a vessel and laser beams are reflected therein in order to achieve a three-dimensional measurement of the inside of the furnace or vessel as an actual value. These actual values are then compared with reference values, and consequently a gunning lance is guided in a controlled manner in order to inject refractory material taking into account a number of physical variables in relation to the vessel.

In contrast, the underlying object of the present invention is to devise a method by means of which a refractory lining of a vessel receiving molten metal can be repaired with improved precision and quality.

According to the invention, this object is achieved by the features of Claim 1 and the features of the device according to Claim 8.

The method according to the invention makes provision such that before, during and/or after the supplying at least a partial region of the refractory lining of the vessel to be repaired or the gunning jet is recorded photographically with visualisation of the temperature ranges, and this results in an evaluation with regard to different parameters, such as properties, layer thickness and/or distribution of the supplied material.

It has been demonstrated that by means of this visualisation of the temperature ranges of the areas to be repaired and of the refractory material during supplying different parameters can be established very accurately during supplying, and as a result optimal coating of the wall lining can be achieved.

Very advantageously the device comprises at least one imaging unit, preferably a thermal imaging camera, by means of which this number of pictures with visualisation of the temperature ranges is recorded from the outside of the vessel.

This recording of the current state of the supplying of the refractory material to the areas in the wall lining of the vessel to be repaired makes it possible, following a comparison with target specifications from stored pictures, to immediately change the actuation of this supplying apparatus and/or to adapt the pre-programmed control to subsequent treatments.

Other advantageous details of this method within the framework of the invention are defined in the dependent claims.

An exemplary embodiment of the invention is described in more detail below by means of drawings. These show as follows:

FIG. 1 is a diagrammatic illustration of a device with a thermal imaging camera and of a metallurgical vessel shown partially in section, for implementing the method according to the invention; and

FIG. 2 is a photographic picture produced by means of a thermal imaging camera according to FIG. 1 primarily of the inside of the vessel and of a gunning lance with the gunning jet during injection of refractory material.

FIG. 1 shows diagrammatically a metallurgical vessel 10 with a steel jacket 11 and a refractory lining 12 consisting of a wall lining with refractory bricks and optionally additionally of gunning on layers. The metallurgical vessel 10 can be, for example, a ladle containing molten metal or a tundish in continuous casting plants or also converters or electric furnaces.

With these metallurgical vessels 10 it is normal and necessary to carry out a repair of the refractory lining 12 at the worn areas 13 or also on the entire inner wall 10′ after a specific operating time by means of an supplying apparatus 15 known in its own right as a manipulator or as a robot, this taking place in the hot state of the respective vessel so that this material to be supplied dries within a reasonable period of time and in so doing connects sufficiently to the existing wall lining.

This supplying apparatus 15 has a gunning lance 16 with at least one injection head 17, by means of which preferably fluidized refractory material is supplied by a gunning jet 18 that has been generated. The angular gunning lance 16 with a transversely disposed outlet nozzle 17′ is on the one hand rotated by the adjustable supplying apparatus 15 during supplying and additionally moves as required in the axial direction so that the vessel 10 can also be provided with gunning material in the height direction 19.

According to the invention, before, during and/or after supplying at least a partial region of the areas 13 of the refractory lining 12 of the vessel 10 to be repaired or the gunning jet 18 is recorded photographically with visualisation of the temperature ranges, and this can result in an evaluation with regard to different parameters, in particular with regard to the properties, layer thickness and/or the distribution of the supplied material.

Advantageously, for this purpose a device 20 with at least one imaging unit, preferably a thermal imaging camera 21, is used that is positioned outside of the vessel 10 and by means of which, preferably during supplying, it is recorded by a number of photographic pictures 25 with visualisation of the temperature ranges 26, 27, 28, such a picture 25 being illustrated in FIG. 2.

This device 20 is positioned sufficiently far away from the vessel 10, outside of its centre axis and to the side of the supplying apparatus 15 so that the camera 21 forms a conical receptacle 22 that records this partial region with approximately the opening 10″ of the vessel 10 and additionally the gunning jet 18 with the surface 18′ in the lining 12 upon which the latter acts.

In addition, this device 20 is protected from the heat radiation from the vessel by protective shields or similar (not detailed) so that the camera does not exceed the specified heating temperatures.

According to this picture 25 according to FIG. 2 corresponding colours are allocated to these specific temperatures of a respective temperature range 26, 27, 28. Depending on the use of the type of heat imaging camera 21 different colours can be provided for the same temperatures.

These pictures 25 of the imaging unit can be taken in real time during supplying of the refractory material here and parameters which are recorded and which are immediately evaluated are compared with target specifications of pictures in the supplying apparatus and the supplying apparatus is correspondingly actuated.

Needless to say, within the framework of the invention one or a number of photographic pictures 25 can also be produced only before and/or after supplying. Occasionally, this is dependent upon the extent of the areas 13 to be repaired. With a relatively small repair one picture 25 before and after supplying may suffice. With a picture after supplying one can additionally establish whether the gunned on material has become detached again due to poor adhesion.

Cameras which work with infrared radiation and which record a temperature range between approximately ambient temperature and advantageously at least approximately 1,500° C. are especially suitable as thermal imaging cameras 21. Suitable as examples are thermal imaging cameras made by FLIR, T600 series or by InfraTec of the VarioCAM type range with a maximum definition of over 500 pixels which are available on the market.

Furthermore, with these images according to the invention different parameters of the gunning jet can be evaluated, occasionally the delivery pressure, the loading, the gunning angle of the jet, the distance between the gunning lance and the inside of the vessel and/or the geometry of the nozzle outlet of the gunning lance. The temperature of the refractory material upon passing out of the gunning head generally corresponds approximately to ambient temperature. However, depending on the requirements a higher temperature can be provided, for example for the purpose of tempering the supplied material.

In addition, the pictures of the imaging unit can be stored and be evaluated by calculations by means of a software programme and analyses resulting from the latter, and so the control of the lance for the current and also the subsequent repair inserts can be changed and so improved.

Another advantage within the framework of the invention is that the wall thicknesses of the refractory lining before and after supplying can be calculated from the pictures and the determined temperature ranges.

The invention is sufficiently displayed by the above exemplary embodiment. However, in principle more than one thermal imaging camera could also be provided. Not all possible evaluations from these pictures are described either. With sufficient heat insulation this type of camera could also be disposed within the vessel, preferably in the gunning head, and is positioned here, however, such that the gunning jet is recorded.

This photographic visualisation of the temperature regions could also take place by means of video recordings.

The repair could also basically take place at outlet openings on the vessels. 

1. A method, in particular for repairing a refractory lining of a metallurgical vessel (10) in the hot state, wherein this repair takes place by means of a supplying apparatus (15), recording of at least the worn regions and a monitoring of the repair taking place by means of a device (20), characterized in that before, during and/or after the supply of at least a partial region of the areas (13) of the refractory lining (12) of the vessel (10) to be repaired respectively the gunning jet (18) is recorded photographically with visualisation of the temperature ranges (26, 27, 28), and this results in an evaluation with regard to different parameters such as properties, layer thickness and/or distribution of the supplied material.
 2. The method according to claim 1, characterized in that the device (20) comprises at least one imaging unit, preferably a thermal imaging camera (21), by means of which a number of photographic pictures (25) with visualisation of the temperature ranges (26, 27, 28) are produced from the outside of the vessel (10) before, during and/or after supplying.
 3. The method according to claim 1, wherein the device (20) is positioned sufficiently far away from this vessel (10) and to the side of the supplying apparatus (15) so that the thermal imaging camera (21) forms a conical receptacle (22) that records this partial region of the areas (13) to be repaired with approximately the opening (10″) of the vessel (10) and additionally the gunning jet (18) with the surface (18′) upon which the latter acts.
 4. The method according to claim 1, wherein the pictures (25) of the imaging unit are stored and evaluated by calculations by means of a software programme and analyses resulting from the latter.
 5. The method according to claim 1, wherein the pictures (25) of the imaging unit are taken in real time during supplying of the refractory material, and parameters for the supplying with the supplying apparatus (15) are compared here with target specifications of stored pictures and the supplying apparatus (15) is immediately actuated during supplying and/or the pre-programmed control is adapted.
 6. The method according to claim 1, wherein there is provided as an supplying apparatus (15) an injection apparatus (17) with at least one gunning lance (16) with which the refractory material is supplied by a generatable gunning jet (18), different parameters of the same, occasionally the delivery pressure, the loading, the gunning angle of the jet, the distance between the gunning lance and the inside of the vessel and/or the geometry of the nozzle outlet of the gunning lance being able to be identified or being able to be determined directly or indirectly on the basis of the pictures of the imaging unit.
 7. The method according to claim 1, wherein the wall thicknesses of the refractory lining (12) before and after supplying can be calculated from the pictures (25) and the determined temperature ranges (26, 27, 28).
 8. A device for implementing the method according to claim 1, which comprises at least one imaging unit, preferably a thermal imaging camera (21), by means of which pictures with visualisation of the temperature ranges are produced.
 9. The device according to claim 8, characterized in that the thermal imaging camera (21) is based on infrared radiation and with it, the temperatures ranges are visualized by different colours.
 10. The device according to claim 8, wherein a temperature range between approximately ambient temperature and at least 1,500° C. can be recorded with the thermal imaging camera (21).
 11. The device according to claim 8, wherein at least one imaging unit, preferably a thermal imaging camera (21), is disposed within the vessel (10), preferably in the injection head (17). 